The operation of two operating systems loaded on a computer, more precisely in the random access memory of a computer, not only alternatively, but alternately without restarting the computer is known.
Thus, WO 98/09225 discloses an operating system for real time extension for conventional, intrinsically not real timable, Microsoft Windows systems through special microkernels.
DE 44 06 094 C2 also discloses a real time extension of conventional Microsoft Windows systems by means of a complete real time operating system, which can also be run separately, i.e. independently of Windows on a computer. The secondary real time operating system has direct access to a single subset of the processor register and hardware components of the computer.
It is also known to emulate under an operating system a virtual computer or machine on which a second operating system can run. The secondary operating system is under the control of the monitor program emulating the virtual computer. The secondary operating system cannot directly access all the processor registers, but instead this only takes place under the control of the monitor program. It is problematical in the prior art that the source code of at least one of the operating systems must be known, because during operation in parts thereof not disclosed normally by the supplier intervention takes place or changes must be made to such parts and in particular the same parts on at least one of the operating systems. It is also disadvantageous if one operating system must run “under” another, i.e. is embedded in the latter.